JPH1166545A - Transparent magnetic recording media using wax dispersion particles - Google Patents

Abstract

(57) Abstract: Provided is a magnetic recording medium having a silver halide photographic photosensitive layer free from scratches and having no magnetic information error by using a photographic support wax dispersion having a magnetic recording layer. In a magnetic recording medium having a magnetic recording layer containing at least one magnetic particle on a support, an average primary particle size is provided in at least one of the same layers on the magnetic recording layer side and / or in a different layer. Contains two or more kinds of inorganic or organic particles having different melting points, and has a melting point of at least 90 in the same layer or / and a different layer on the magnetic recording layer side.
A transparent magnetic recording medium coated with a wax dispersion at a temperature of at least ℃.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium which is excellent in manufacturing suitability and stability, and has improved transport / running stability, stain resistance of a magnetic head, and scratch resistance related to input / output errors of magnetic information. It is.

[0002]

2. Description of the Related Art The magnetic recording layer of a magnetic recording medium such as an audio tape, a video tape, and a floppy disk has no optical transparency. U.S. Pat. No. 5,491,051 describes a photographic element having a transparent magnetic recording layer with excellent magnetic and photographic properties that can be used repeatedly. These elements are used for the purpose of handling the web during production, transporting it in cameras, processors, magnetic input / output devices, etc., running, and providing scratch resistance during production or use. A slip agent is used on the layer side. A wax having a long-chain aliphatic hydrocarbon group gives excellent slipperiness, but has several problems in the use of dissolution, dispersion, coating, etc. in order to maximize its properties. I was As a method of applying a derivative of a higher fatty acid which is a wax, a derivative of a higher alcohol and a higher hydrocarbon, there is a method of applying by dissolving in a solvent, and a method of applying a wax dispersion.
Since both are heated at the time of drying, for example, in the case of carnauba wax, the wax adheres and accumulates on a portion, for example, a roller, which comes into contact with the application surface during or after drying, and retransfers to the application surface to deteriorate the surface state. was there. In order to impart uniformity of the coating film, a method of applying a dispersion is preferred. This is disclosed, for example, in JP-A-7-133488,
293188, 3-258339, 3-199
267 and 1-222584. However, these methods have insufficient dispersion stability of the wax particles in the coating solution and cannot prevent coagulation and sedimentation. In addition, higher scratch resistance, running properties, and transportability are required from requirements such as input / output of magnetic recording information, and the scratch resistance and transportability are not sufficient. The problem of scratch resistance is a major problem when information is input / output to / from the magnetic recording layer when handling a photosensitive material having a magnetic recording layer in the backing layer, and causes an error due to space loss. The causes of space loss are mainly wax applied to the backing layer, abrasion powder of the magnetic recording layer, dust attached when handling the photosensitive material,
Sensitive material debris, dust in the atmosphere, dry matter of the developing solution, etc., are attached to and deposited on the surface of the magnetic head when the film is running, thereby increasing the gap between the film and the magnetic head. Space loss occurs, and a magnetic input / output error occurs. There is a method of preventing the accumulation of dirt on the head surface with a polishing agent. However, if an effective amount is added, problems such as reduction in transparency, shortening of the life of the magnetic head, and generation of dust due to falling off of the polishing agent occur.

[0003]

Therefore, a first object of the present invention is to prevent the surface condition from being deteriorated due to retransfer from a wax production machine at the time of applying a wax-containing layer, and to be excellent in dispersion stability.
The second purpose is to improve the scratch resistance, running properties, and transportability of the magnetic recording layer, and the third purpose is to be substantially transparent and to prevent contamination of the magnetic head to reduce the input / output errors of magnetic information, thereby being optimal. An object of the present invention is to provide a transparent magnetic recording medium having an excellent surface shape.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have attained the above object by the following means. (1) In a magnetic recording medium having a magnetic recording layer containing at least one magnetic particle on a support, at least one of the same layers on the side of the magnetic recording layer or / and a different layer has an average primary particle size. A dispersion of a wax having a melting point of 90 ° C. or more is applied to at least one of the magnetic recording layer side and / or different layers containing two or more kinds of inorganic or organic particles having different diameters. A transparent magnetic recording medium, comprising: (2) The transparent magnetic recording medium according to (1), wherein the wax mainly comprises one or more compounds represented by formulas (I), (II) or (III). General formula _{(I) R 1 -X 1 -R} 2 Formula _{(II) R 3 -X 2 -R} 4 - (X 3 -R 5) in _n Formula (III) R ₆ OBH formula, R ₁ to R ₃ , R ₅ and R ₆ are a substituted or unsubstituted saturated or unsaturated hydrocarbon group having 10 to 70 carbon atoms, including straight, branched and cyclic, and R ₄ is a divalent or more substituted C 10 to C 50 hydrocarbon group. Alternatively, it is an unsubstituted saturated, unsaturated or linear, branched or cyclic hydrocarbon group. X ₁ ~X ₃ is -COO
-, -OCO-, -CONR-, -NRCO-,
n is an integer of 1 or more. B is a polyalkylene oxide chain. (3) The dispersion is prepared by using a high-pressure homogenizer in a closed tube from the homogenizing chamber to the processing liquid discharge port and using a device having a back pressure applying device behind the homogenizing chamber ( 1)
Or the transparent magnetic recording medium according to (2). (4) The transparent magnetic recording medium has at least one silver halide emulsion layer on the opposite side to the magnetic recording layer with the support interposed therebetween (1) to (3).
3. A transparent magnetic recording medium having a silver halide emulsion layer according to item 1. (5) The transparent magnetic recording medium according to any one of (1) to (4), wherein the coating amount of the dispersion is 16 mg / m ² or more. (6) 25% relative humidity 60% of the transparent magnetic recording medium,
The transparent magnetic recording medium according to any one of (1) to (5), wherein an optical contact area at a wavelength of 0.5 μm under a load of 16 kg / m ² is from 20% to 80%.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, wax is mainly used.
Higher fatty acids or their derivatives, higher alcohols or
Is one or more selected from derivatives or higher hydrocarbons
It is preferred to consist of a compound of the following. Melting point is 90 ° C
And preferably 95 ° C. or higher. Induction of higher fatty acids
Body and higher fatty acid derivatives include higher fatty acid ester
, Higher fatty acid amide, higher fatty acid polyhydric alcohol
Stele, polyhydric fatty acid ester of higher fatty acid alcohol
Such as paraffin wax and polyether.
Tylene wax, Fischer-Tropsch wax, etc.
Is raised. In particular, the following general formula (I), (II) or
The compound represented by (III) is preferred. General formula (I) R₁-X₁-R_Two General formula (II) R_Three-X_Two-R_Four− (X_Three-X_Five)_n General formula (III) R₆OBH where R₁~ R_Three, R_Five, R₆Is also substituted with 10 to 70 carbon atoms
Or unsubstituted, saturated or unsaturated, including linear, branched, and cyclic
Saturated hydrocarbon radical, R_FourIs divalent or higher having 10 to 50 carbon atoms
Saturation including substituted or unsubstituted linear, branched and cyclic
Or an unsaturated hydrocarbon group. X₁~ X_ThreeIs -COO
-, -OCO-, -CONR-, -NRCO-,
n is an integer of 1 or more. B is a polyalkylene oxide
Chain. Where R₁~ R_Three, R_FiveHas 10 to 7 carbon atoms
0, more preferably 15-50 substituted or unsubstituted
Saturated or unsaturated hydrocarbons including linear, branched and cyclic
Group, R _FourHas 10 to 50 carbon atoms, more preferably 12 to 2 carbon atoms.
5 or more divalent substituted or unsubstituted linear, branched, or cyclic
And saturated or unsaturated hydrocarbon groups. n is 2
Is an integer greater than or equal to.

In the general formula (I), the total number of carbon atoms is 20 to 120.
Is preferred. It is more preferably from 25 to 100, still more preferably from 30 to 80. In the general formula (II), the total carbon number is preferably from 20 to 150. More preferably 40 to 13
0, more preferably 50 to 120. X ₁ to X ₃ is -COO -, - OCO -, - CONR -, - NRCO-
And R represents H or an alkyl group having 8 or less carbon atoms. As the alkylene oxide chain, ethylene oxide and propylene oxide are preferable, and ethylene oxide is more preferable. The degree of polymerization is not particularly limited, but is preferably from 10 to 120.

[0007] Examples of the substituent include a halogen atom, a hydroxy group, a cyano group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amino group, an acylamino group, a sulfonyl group, and a sulfinyl group. , An aryl group and an alkyl group. These groups may further have a substituent. Preferred substituents include
A halogen atom, a hydroxy group, an alkoxy group, an alkylthio group, an alkoxycarbonyl group, an acylamino group, a sulfonylamino group, an acyl group and an alkyl group.
As the halogen atom, a fluorine atom and a chlorine atom are preferable. Alkoxy group, an alkylthio group, an alkyl group of the alkoxycarbonyl groups are the same alkyl group R ₂ described above. The amino group of the acylamino group or the sulfonylamino group may be an N-substituted amino group, and the substituent is preferably the above-mentioned alkyl. The group bonded to the acylamino group, the carbonyl group of the acyl group and the sulfonyl group of the sulfonylamino group are an alkyl group and an aryl group, and the above-mentioned alkyl group is preferable.

In the present invention, the expression that the wax mainly comprises one or more compounds means that the total amount of the one or more compounds represented by the general formula is 70% by weight or more. Waxes may be natural or synthetic. Natural products,
Alternatively, even in the case of synthetic products, synthetic compounds using higher fatty acids or alcohols as raw materials include those having different numbers of carbon atoms, straight-chain and branched ones, and mixtures thereof. No problem. Specific examples of preferred compounds represented by formulas (I), (II) and (III) are shown below.

(W-1) C ₁₁ H ₂₃ CO ₂ C ₅₀ H ₁₀₁ Melting point 104 ° C. (W-2) C ₃₀ H ₆₁ OOC (CH ₂ ) ₁₈ CO ₂ C ₃₀ H ₆₁ Melting point 90 ° C. (W-3) C ₃₀ H ₆₁ OOC (CH ₂ ) ₁₈ CO ₂ CH ₂ CH ₂ C ₈ F ₁₇ Melting point 92 ° C (W-4) C ₃₀ H ₆₁ OOC (CH ₂ CH ₂ O) CH ₂ CH ₂ CO ₂ C ₃₁ H ₆₁ Melting point 93 ℃ (W-5) CH ₃ CO ₂ C ₅₀ H ₁₀₁ Melting point 91 ℃ (W-6) C ₇ H ₁₅ CO ₂ C ₅₀ H ₁₀₁ Melting point 104 ℃ (W-7) CH ₃ CO ₂ C ₄₀ H ₈₁ Melting point 91 ° C (W-8) C ₇ H ₁₅ CO ₂ C ₄₀ H ₈₁ Melting point 93 ° C. (W-9) C ₁₁ H ₂₃ CO ₂ C ₄₀ H ₈₁ Melting point 90 ° C. (W-10) C ₁₈ H ₃₇ NHCO (CH ₂ ) ₁₀ CONHC ₁₈ H ₃₇ Melting point 130 ° C (W-11) C ₄₀ H ₈₁ OCOCH ₂ CH ₂ CO ₂ H Melting point 96 ° C (W-12) C ₄₀ H ₈₁ OCOCH ₂ CH ₂ CO (CH ₂ CH ₂ O) _4.5 H Melting point 94 ° C (W-13) C ₄₀ H ₈₁ OCOCH ₂ CH ₂ CO ₂ (CH ₂ CH ₂ O) _8.5 H Melting point 101 ° C (W-14) C ₄₀ H ₈₁ OCOCH ₂ CH ₂ CO ₂ (CH ₂ CH ₂ O) _22.5 H Melting point 97 ° C (W-15) C ₄₀ H ₈₁ OCOCH ₂ CH ₂ CO ₂ (CH (CH ₃ ) CH ₂ O) _6.5 H Melting point 91 ° C

[0010] _{(W-16) C 40 H} 81 OCOCH 2 CH 2 CO 2 (CH 2 CH 2 O) 8.5 CH 3 mp 96 ℃ (W-17) C 30 H 61 O (CH 2 CH 2 O) 2. ₆ H mp 95 ℃ (W-18) C 30 H 61 O (CH 2 CH 2 O) 10 H mp 94 ℃ (W-19) C 40 H 81 O (CH 2 CH 2 O) 13 H mp 100 ° C. ( W-20) C ₅₀ H ₁₀₁ O (CH ₂ CH ₂ O) ₄ H Melting point 106 ° C (W-21) C ₅₀ H ₁₀₁ O (CH ₂ CH ₂ O) ₁₆ H Melting point 107 ° C (W-22) C _{50 H 101 OCOCH 2 CH 2 CO} 2 H melting point 103 ℃ (W-23) C 50 H 101 OCOCH 2 CH 2 CO 2 (CH 2 CH 2 O) 8.5 H mp 103 ℃ (W-24) C 30 H ₆₁ OCOCH ₂ CH ₂ CO ₂ (CH ₂ CH ₂ O) COCH ₂ CH ₂ CO ₂ C ₃₀ H ₆₁ Melting point 93 ° C (W-25) C ₅₀ H ₁₀₁ CO ₂ H Melting point 109 ° C (W-26) CH ₃ (CH ₂ ) ₇ CHI-CHCl (CH ₂ ) ₇ CO ₂ C ₄₀ H ₈₁ Melting point 91 ° C (W-27) C ₁₇ H ₃₅ CO ₂ C ₅₀ H ₁₀₁ Melting point 95 ° C (W-28) C ₈ H ₁₇ CH (OH) C ₆ H ₁₂ CO ₂ C ₅₀ H ₁₀₁ Melting point 97 ° C

[0011] These compounds are partially described, for example, in JP-A-58-90633. The above waxes may be used alone or in combination.

The wax particles can be prepared in water or in an organic solvent. Particles can be prepared in water by melting at a temperature higher than the melting point of the constituents of the particles and emulsifying in water, by dissolving in an organic solvent and emulsifying in water, or by using a ball mill or sand grinder from large particles. There is a method of crushing. Such methods for producing particles are described in books such as cut rice, pebbles, edited by Hidaka, "Emulsification and Dispersion Technology Application Handbook" (Science Forum Edition) and the like. As a method of preparing particles in an organic solvent, a method of heating and dissolving in an organic solvent, cooling and precipitation while stirring, melting at a temperature equal to or higher than the melting point of the components constituting the particles or heating and dissolving in an organic solvent, at room temperature Alternatively, a method of adding a cooled organic solvent to precipitate by cooling, a method of crushing large particles with a ball mill or a sand grinder, and the like can be mentioned. The method for preparing particles in water or an organic solvent according to the present invention includes heating and dissolving in an organic solvent, adding to normal or cooled water or an organic solvent to precipitate by cooling, an ultrasonic disperser, a high-pressure homogenizer. The method of dispersing in is preferred. The organic solvent used for dispersion is not particularly limited, but ketones, alcohols, and ether alcohols are preferred.

When water or an organic solvent is used as the dispersion medium,
As a method for producing the wax particles, it is most preferable to use a high-pressure homogenizer. In particular, among the high-pressure homogenizers, a high-pressure homogenizer having a closed tube between the homogenizing chamber and the processing liquid discharge port and having a back pressure applying device therebetween is particularly preferable. Further, a high-pressure homogenizer in which a heat exchanger for heating the processing liquid is installed immediately before the homogenizing chamber and a heat exchanger for cooling the processing liquid is installed between the homogenizing chamber and the back pressure applying device is a dispersion of the present invention. The best machine. By using the above-described disperser, the wax particles in the processing liquid are melted immediately before the processing in the homogenizing chamber, and further generate heat when being processed, but are cooled under high pressure by the back pressure applying device, and thus dispersed after the processing. The boiling of the liquid is suppressed and a fine wax dispersion can be stably obtained. When a wax dispersion is prepared using this apparatus, the dispersion pressure is preferably in the range of 200 to 5000 kg / cm ² ,
Is more preferably in the range of 1700 kg / cm ² to 1700 kg / cm ² . The concentration of the wax in the dispersion is not particularly limited, but is preferably in the range of 1 to 40% by weight. The particle size of the wax dispersion is not particularly limited, but is preferably in the range of 0.005 to 5 μm, and more preferably in the range of 0.02 to less than 0.2 μm.

Next, the backing layer will be described. The backing layer referred to in the present invention means a side on which one surface of a support is provided with an undercoat layer and at least one photosensitive silver halide emulsion layer is provided (hereinafter, abbreviated as a photosensitive layer). The layers provided on the opposite side of the support are collectively called a backing layer. This backing layer may be a layer coated on an undercoat layer as in the case of the photosensitive layer, or may be directly coated on a surface-treated support without an undercoat layer. The undercoat layer may be composed of two or more layers in order to improve the adhesion between the support and the backing layer.
However, in the present invention, when a backing layer is used, even if it has an undercoat layer, the layer excluding the undercoat layer is generically referred to. The backing layer is provided mainly for providing various functions required in addition to the photographic performance of the photosensitive material. The various functions include, for example, prevention of generation of static marks, prevention of adhesion and slipperiness in the production and handling of photosensitive materials, prevention of curling, prevention of unnecessary light entering the photosensitive layer from the support side, and furthermore, exposure to light. It records information such as material production and shooting conditions, etc. To provide these functions, it is called an antistatic agent, matting agent, slip agent, anti-curl agent, light absorber, filter dye, ultraviolet absorber The compound to be used, ferromagnetic fine particles, and the like are used, and a binder, a curing agent, a plasticizer, a surfactant, a coating aid, and the like for supporting these compounds and the like are also used. The backing layer provided to provide the various functions described above contains some of the compounds described above according to the additional functions required for the light-sensitive material. These compounds may be contained in one layer, but it is preferable to use two or more layers depending on the function to be provided. In addition, two or more layers having the same function to be provided may be provided, and an intermediate layer may be provided between the function layers to be provided.

The wax of the present invention can be applied by dispersing or dissolving in water or a known organic solvent as described above. Further, it is particularly preferable to apply the wax with a binder having a film-forming ability, from the viewpoint of improving the wax-coated surface state and increasing the film strength of the wax-containing layer. As the binder, known thermoplastic resins, thermosetting resins, radiation-curable resins, reactive resins and the like can be used,
These may be used in combination. The layer containing the wax dispersion of the present invention may be applied anywhere on the backing layer side, and particularly preferred addition layers are a magnetic recording layer and an outermost layer. The amount of the wax used in the present invention is 2 to 100 mg / kg in order to exhibit sufficient scratch resistance and slipperiness.
m ² is required, preferably 16～50Mg / m ^2, particularly preferably a 16~40mg / m ^2. The wax layer is desirably dried or heat-treated at a temperature equal to or higher than the melting point of the wax. The slip performance of the surface on the backing layer side provided by the slip agent of the present invention is 25% when the magnetic recording layer is provided.
1 ° C., 5% diameter stainless steel balls at 60% RH
The dynamic friction coefficient before and after the development process evaluated with a load of 00 g is
Both are 0.03 to 0.20, preferably 0.04
To 0.15, more preferably 0.05 to 0.14, particularly preferably 0.06 to 0.13. In addition, it is particularly preferably 0.05 to 0.12. When the dynamic friction coefficient is larger than 0.20, the photosensitive material is significantly damaged when the photographic system is running.

As the solvent for dispersing the wax or the solvent for coating the wax-containing layer, water, an organic solvent, a mixed solution of water and an organic solvent, or the like can be used. Organic solvents include alcohols (methanol, ethanol, isopropanol, butanol, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), esters (methyl such as acetic acid and formic acid,
Ethyl, propyl, butyl esters, etc.), hydrocarbons (hexane, cyclohexane, etc.), halogenated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride, etc.), aromatic hydrocarbons (benzene, toluene, xylene, benzyl alcohol, etc.) ), Amides (eg, dimethylformamide, dimethylacetamide, n-methylpyrrolidone), ethers (eg, diethyl ether, dioxane, tetrahydrofuran), and ether alcohols (eg, 1-methoxy-2-propanol). Among them, alcohols, ketones and esters are preferred.

Further, as a preferable known slipping agent which can be used in combination, a silicone compound which is commercially available or can be obtained by synthesis can be exemplified. Polyorganosiloxanes are preferred as the silicone compound. Commercially available silicone compounds are available from Dow Corning, USA and BYK Chemi, Germany.
Various structures are sold as commercially available chemical products by e-company, Shin-Etsu Chemical Co., Ltd., Toshiba Silicone Co., Ltd., Toray Silicone Co., Ltd., Nippon Unicar Co., Ltd., and Chisso Co., Ltd. Available. Also, these commercially available silicones can be easily derivatized by ordinary chemical reactions using them as raw materials. It is also preferable to use these slip agents in combination.

In the wax-containing layer, a binder may be used if necessary. As the binder, known compounds, for example, various gelatins (eg, alkali treatment, acid treatment, enzyme treatment, modification (phthalation, succination, trimellitization, etc.), modification, gelatin having a special molecular weight distribution, etc.),
Substituted or unsubstituted celluloses, natural gum arabic, soluble in hydrophilic binders such as dextran and ordinary organic solvents and completely or almost insoluble in water such as a developing solution,
And a film-forming hydrophobic binder, for example, polystyrene, polymethyl methacrylate, polyvinylidene chloride, polyacrylonitrile, homo or copolymers such as polyvinyl acetate, cellulose diacetate, cellulose triacetate, ethyl cellulose, cellulose nitrate, hydroxypropyl Cellulose, cellulose derivatives such as cellulose propionate,
Further, acetal such as polyvinyl acetal, polyvinyl benzal, polyvinyl formal and the like can be mentioned. These may be used as a mixture of two or more.

In the present invention, gelatin or a substituted or unsubstituted cellulose derivative, particularly a substituted alkyl cellulose, is preferably used as the hydrophilic binder, and a cellulose derivative is preferably used as the hydrophobic binder. In particular, use of hydroxyalkyl (alkyl group having 1 to 5 carbon atoms) celluloses and cellulose diacetate is preferable, and use of hydroxyalkyl (2 to 4 carbon atoms) cellulose is most preferable.

When used as a hydrophilic binder, it is desirable to use a hardener to make it water-insoluble or hardly soluble. In the case of various gelatins, known hardeners can be used.

The inorganic particles used in the present invention include aluminum oxide (α-alumina, γ-alumina, corundum, etc.), chromium oxide (Cr ₂ O ₃ ), iron oxide (α-Fe ₂ O ₃ ),
Silica, colloidal silica, titanium dioxide, zinc oxide,
Oxides such as tin oxide, silicon carbide (SiC), carbides such as silicon carbide and titanium carbide, fine powders such as diamond,
Calcium carbonate, aluminum hydroxide, barium sulfate,
Strontium barium sulfate, manganese colloid and the like can be mentioned. Examples of the organic polymer particles include resin particles such as polytetrafluoroethylene, cellulose acetate, polystyrene, polymethyl methacrylate (PMMA), polypropyl methacrylate, polymethyl acrylate, and polyethylene carbonate, starch, and the like. Are also mentioned.

Further, acrylic esters, methacrylic esters, itaconic diesters, crotonic esters, maleic diesters, phthalic diesters, styrene derivatives, vinyl esters, acrylamides, vinyl ethers, allyl compounds, vinyl ketones, vinyl diesters Monomers such as articulated compounds, allyl compounds, acrylonitrile, methacrylonitrile, polyfunctional monomers, etc.
The polymer compound which is a kind or two or more kinds of polymers may be formed into particles by various means, for example, a suspension polymerization method, a spray drying method, or a dispersion method. Other examples include siloxane resin particles and benzoguanamine resin particles.

The preferred use of these particles in the present invention is described below. Inorganic and / or different average primary particle diameters
In addition, it is necessary that at least one of the organic polymer particles be contained in at least one of the layers on the magnetic recording layer side (including the case where the same material type has a different particle size). At this time, the average primary particle diameter of at least one particle is 0.2 μm or more.
0 μm or less, preferably 0.3 to 0.9 μm, and the average primary particle diameter of at least one particle is 0.01 μm.
m or more and less than 0.2 μm, preferably 0.015 to
Preferably, the thickness is 0.15 μm. When the average primary particle size exceeds 1.0 μm, when used as a transparent magnetic recording medium with a silver halide emulsion layer, there is a possibility that surface projections may damage the emulsion layer surface or cause problems such as a reduction in graininess. Further, in order to efficiently exert the effect of the surface shape, it is particularly preferable that these particles are contained in the magnetic recording layer located on the outermost layer side and / or the layer adjacent to the magnetic recording layer.

In a transparent magnetic recording medium containing two or more kinds of inorganic and / or organic polymer particles having different average primary particle diameters, fine projections made of particles having a small average primary particle diameter are finely polished. In the case of a transparent magnetic recording medium having a silver halide emulsion layer accompanied by a developing process, a dried product (dirt) of the developing solution adheres to and remains on the surface of the magnetic recording layer. It was found that dirt could be finely and uniformly dispersed in the dried matter using the dirt protrusions as nuclei. Since the microprojections made of these microparticles exist between the coarse projections made of large particles, the coarse projections secure the space between the magnetic head and the medium,
It is possible to realize a transparent magnetic recording medium in which it is difficult to transfer finely dispersed stains to a magnetic head. Further, the coarse projections can function as a coarse polishing film, and can be realized as a transparent magnetic recording medium having a very high magnetic head cleaning ability, having a coarse surface and a fine surface. The particle size distribution of the particles used is
It is preferable that the particles are sharp, and as particles having a large average primary particle diameter, PMMA, α-alumina, silica, or / and siloxane particles, which are easy to obtain a sharp particle size distribution, are preferable, and the average primary particle diameter is large. As small particles, it is easy to obtain particles smaller than 0.2 μm.
α-alumina, γ-alumina, θ-alumina, PMMA, silica, colloidal silica, and / or titanium dioxide particles are preferred. However, this is not the case. Among the above, it is preferable that at least α-alumina having a Mohs hardness of 9 is contained in that the magnetic head itself can be polished to a mirror surface.

Specific examples of the particles having a large average primary particle diameter include, but are not limited to, the following. (Α-Alumina) “AKP30” “A” manufactured by Sumitomo Chemical Co., Ltd.
KP20, AKP15, AKP10, Sumicorundum, HIT5
0 ", Reynolds" ERC-DBM ", Norton" Norton-E600 "(silica) Nippon Shokubai Co., Ltd." Seahoster KEP30 "
Seahoster KEP50, Seahoster KEP70, Seahoster
KEP90, Seahoster KEP100, Seahoster KEP150 (Siloxane) Tospearl manufactured by Toshiba Silicone Co., Ltd.
105, Tospearl 108, XC99-A8808 (PMMA) Soken Chemical Co., Ltd. "MX-100""MX-150", Nippon Paint Co., Ltd. "P-1430""P-5000", Specific examples of the particles having a small average primary particle diameter include the following.

(Α-alumina) “HIT100”, “HIT80”, “HIT80G”, “AKP80”, “AKP50” manufactured by Sumitomo Chemical Co., Ltd. (γ-alumina) “AKP-G015” manufactured by Sumitomo Chemical Co., Ltd. θ-alumina) “AKP-G008” manufactured by Sumitomo Chemical Co., Ltd. (silica) “Seahoster KEP10” manufactured by Nippon Shokubai Co., Ltd. (colloidal silica) “MEK-ST” manufactured by Nissan Chemical Co., Ltd.
"MLBK-ST""Methanol silica gel""MA-ST-M"
"IPA-ST" (PMMA) "MS-300K" and "MS-300S" manufactured by Soken Chemical Co., Ltd.
”, Nippon Paint Co., Ltd.“ P-8000 ”“ S-5001 ”“ S
-5002 "," P-5001 "," P-5002 "The amounts of these particles used are described below. The total of two or more types of particles (small to large particles) having different average primary particle diameters is 0.1 wt% or more and 500 wt% of the layer containing these.
It is desirable that: The ratio of the particles having the largest average particle diameter to the particles having the smallest average primary particle diameter is a weight ratio.
2 to 1:30, more preferably 1: 0.3 to 1:15
It is.

The particles having the smallest average primary particle diameter (particles forming microprojections) are 5 mg / m ² or more and 500 mg or less.
/ M ² or less. 500mg /
For performance improvement effect exceeds m ² is already sufficient,
It is not preferable in terms of cost. On the other hand, if it is less than 5 mg / m ² , the effect of improving the magnetic input / output properties will decrease. Further, particles having a large average primary particle diameter (particles forming coarse projections)
It is desirable to add the transparent magnetic recording medium at 5 ° C. and 60% RH under a load of 16 kgf / cm ^{2 so} that the optical contact area at a wavelength of 0.5 μm is 20% or more and 80% or less. (The larger the particle size and the amount used, the smaller the optical contact area,
This corresponds to an increase in the spacing between the head and the medium. The measuring method will be described later. If it is larger than 80%, the effect of preventing dirt from being transferred to the magnetic head will be insufficient, and if it is smaller than 20%, the space loss loss of the magnetic output will increase to some extent, and both are not preferred. Two or more kinds of inorganic and / or organic polymer particles having different average primary particle diameters may be contained in the same layer, or may be contained in different layers different from each other.

It is preferable that 90% or more of the particles (including secondary particles) present in the coated layer have a size of 1.0 μm or less. More preferably, it is 95% or more and 1.0 μm or less. This is because the magnetic head can be contacted with the magnetic head very uniformly, and a post-process such as calendering (mirror finishing) is not required. Each of these particles is singly and / or separately dispersed and formed into a slurry, which is added to the coating solution of the layer to be incorporated.
Mixing is preferred because the formulation tolerances such as the stability with time of the coating solution are widened. The thickness of the layer containing the inorganic or / and organic polymer particles is preferably 90% or less of the particle diameter of the particles having the largest average primary particle diameter in the layer in order to sufficiently form projections, More preferably 80%
It is as follows.

When a part or all of the coating solution solvent for the layer containing the inorganic or / and organic polymer particles is used as a solvent capable of dissolving the lower layer of the layer, when the layer containing the particles is coated, Part of the lower layer can be dissolved and the particles can be embedded in the lower layer. In particular, it is effective when the thickness of the particle-containing layer is extremely reduced. In this case, it is preferable that each particle is buried by 30% or more by volume in order to sufficiently retain the particles, and 50% or more is buried. More preferred. The refractive index of the particles used in the present invention is not particularly limited, but the difference with respect to the refractive index of the layer containing the particles is 0.08 or less, more preferably 0.04 or less, and further preferably 0.02 or less. The following is desirable in that transparency of the medium such as haze can be improved.

Particularly preferred magnetic recording media in the present invention include a color reversal film and a color negative film containing a silver halide photosensitive layer. In particular, general-purpose color negative films are preferable. As the silver halide emulsion, usually, those subjected to physical ripening, chemical ripening and spectral sensitization are used. The effect of the present invention is particularly noticeable when an emulsion sensitized with a gold compound and a sulfur-containing compound is used. Additives used in such a process are Research Disclosure Nos. 17643 and 18
716, and the relevant portions are described later.

Known photographic additives which can be used in the present invention are also described in the above two Research Disclosures, and the relevant portions are shown in the following table. Type of Additive RD17643 RD18716 1. Chemical sensitizer page 23, page 648, right column 2. Sensitivity enhancer Same as above 3. Spectral sensitizer, page 23-24, page 648, right column-supersensitizer 649, right column 4 Brighteners page 24 5. Antifoggants, pages 24-25 page 649 right column and stabilizers 6. Light absorbers, filters 24-25 pages 649 right column Luter dyes, purple page 650 left column Agent 7. Stain inhibitor, page 25, right column, page 650, left to right column 8. Dye image stabilizer, page 25 9. Hardener, page 26, page 651, left column 10. Binder, page 26 Same as above. Plasticizer, lubricant page 27, page 650, left column 12. Coating aid, pages 26-27, page 650, right column surfactant

In the present invention, APS (Advanced Photo System)
In the case of a patrone containing a color sensitive material, the total weight of the plastic used for the patrone and the patrone case is usually 1 g or more and 25 g or less, preferably 5 g or more and 15 g or less.
g or less. In the case of APS, the film roll width is 2
Since it is 4 mm, the size of the patrone can be reduced. The patrone of the present invention is not particularly limited in its form. The photographic film to be stored may be a so-called raw film before development or a photographic film that has been processed. Also, the raw film and the developed photographic film may be stored in the same new patrone or different patrones.

[0033]

The present invention will be described in detail below with reference to specific examples, but the present invention is not limited to the examples unless it exceeds the gist of the present invention. (Example 1) A wax dispersion was prepared as follows, and the particle size and the dispersion stability of the wax particles in the coating solution were evaluated. The average particle size was determined as an arithmetic mean by measuring 500 particles with an electron microscope. The dispersion stability of the wax particles in the liquid was determined from the degree of sedimentation of the particles at the bottom of the container after 500 g of the coating liquid was allowed to stand at 25 ° C. for 3 days. No sediment is observed ◎ Slight sediment is observed ○ Sediment forms a sedimentary layer △ Sediment forms a sedimentary layer and the supernatant is transparent × (Dispersion A) Carnauba No. 1 fine powder (hereinafter abbreviated as carnauba fine powder)
15 g, cyclohexanone 32.0 g, 1-methoxy-
12.0 g of 2-propanol was added and dissolved at 90 ° C. This solution was mixed with strongly stirred cyclohexanone 9755.
g, and added while cooling, followed by treatment with an ultrasonic disperser to prepare Dispersion A.

(Dispersion A1) 100 g of Dispersion A was added to 83
It was added to 7 g of isopropyl alcohol to prepare a dispersion A1. (Dispersion A2) 300 g of Dispersion A was added to 637 g of isopropyl alcohol to prepare Dispersion A2. (Dispersion A3) 400 g of the dispersion A1 was heated to 95 ° C. immediately before the homogenizing valve using a high-pressure homogenizer (Microfluidizer (EH110 manufactured by Mizuho Industry Co., Ltd.)) equipped with a back pressure applying device and a heating and cooling device, and 1200 kg
After the treatment at a pressure of / cm ² , the process of cooling to 30 ° C. and discharging the treatment liquid was repeated three times to prepare a dispersion A3. (Dispersion liquid A4) Dispersion liquid A2 was treated in the same manner as dispersion liquid A3 to prepare dispersion liquid A4.

(Dispersions B, B1, B2, B3, B4) In the dispersions A, A1, A2, A3, A4, instead of the fine powder of carnauba, 75 g of the following compound (WT), W-21 7
Dispersions B and B were prepared in the same manner except that 5 g was used.
1, B2, B3, and B4 were created.

(Dispersions C, C1, C2, C3, C4) The same as dispersions A, A1, A2, A3, and A4 except that 75 g of W-28 and 75 g of W-21 were used instead of fine carnauba powder. The dispersions B, C1, C2,
C3 and C4 were prepared.

(Dispersions D, D1, D3) Dispersions A, A
1, W-28 instead of carnauba fine powder in A3
Dispersions D, D1, and D3 were prepared in the same manner except that 180 g and W-21 75 g were used.

The results are shown in Table 1. Using the high-pressure homogenizer of the present invention does not impair the stability of the dispersion even when the concentration of the dispersion is increased.

[0039]

[Table 1]

[0040]

Embedded image

Example 2 1) First layer and undercoat layer For a polyethylene naphthalate support having a thickness of 90 μm, a treatment atmosphere pressure of 0.2 Torr, a partial pressure of H ₂ O in an atmosphere gas of 75%, Glow discharge treatment was performed at a discharge frequency of 30 kHz, an output of 2500 W, and a treatment intensity of 0.5 kV · A · min / m ² . A coating solution having the following composition was applied as a first layer on the support at a coating amount of 5 cc / m ² by using a bar coating method described in Japanese Patent Publication No. 58-4589. Conductive fine particle dispersion (SnO ₂ / Sb ₂ O ₅ particle concentration 50 parts by weight 10% aqueous dispersion, secondary aggregate having a primary particle diameter of 0.005 μm and an average particle diameter of 0.05 μm) Gelatin 0.5 Parts by weight Water 49 parts by weight Polyglycerol polyglycidyl ether 0.16 parts by weight Poly (degree of polymerization 20) oxyethylene 0.1 parts by weight Sorbitan monolaurate Further, after coating the first layer, a stainless steel core having a diameter of 20 cm is applied. Wound, 110 ° C (Tg of PEN support: 119 ° C),
After heat treatment for 48 hours, the support was sandwiched, and a coating solution having the following composition was applied as an undercoat layer to the opposite side of the first layer side by a bar coating method at a coating amount of 10 cc / m ² .

Gelatin 1.01 part by weight Salicylic acid 0.30 part by weight Resorcin 0.40 part by weight Poly (polymerization degree 10) oxyethylene nonylphenyl ether 0.11 part by weight Water 3.53 parts by weight Methanol 84.57 parts by weight n -Propanol 10.08 parts by weight Further, a second layer and a third layer described later are sequentially applied on the first layer, and finally, Example 1 of JP-A-7-287345 is disclosed.
The transparent magnetic recording medium provided with a silver halide emulsion layer was prepared by applying the color negative photosensitive material described in 1) in multiple layers.

2) Second layer (transparent magnetic recording layer) Dispersion of magnetic material Co-coated γ-Fe ₂ O ₃ magnetic material (Hc: 831 Oe, σs: 77.1)
emu / g, σr: 37.4 emu / g, S _BET : 38.7 m ² /
g) 1100 parts by weight, 220 parts by weight of water and a silane coupling agent [3- (poly (degree of polymerization 10) oxyethynyl)
[Oxypropyltrimethoxysilane] 165 parts by weight and kneaded well with an open kneader for 3 hours. The coarsely dispersed viscous liquid was dried at 70 ° C. for 24 hours to remove water, and then heated at 110 ° C. for 1 hour to be processed to produce surface-treated magnetic particles.

Further, the mixture was kneaded again in an open kneader for 4 hours according to the following formulation. The above-mentioned surface-treated magnetic particles 855 g Diacetyl cellulose 25.3 g Methyl ethyl ketone 136.3 g Cyclohexanone 136.3 g

Further, a sand mill (1/1 /
(4G sand mill) at 2,000 rpm for 4 hours. The media used was 1 mmφ glass beads. The above kneading liquid 45 g Diacetyl cellulose 23.7 g Methyl ethyl ketone 127.7 g Cyclohexanone 127.7 g

Further, a third layer coating solution was prepared according to the following formulation. Preparation of Intermediate Solution Containing Magnetic Substance 50.8 g of the above magnetic substance fine dispersion liquid 1914.7 g (solid content: 4.5%, solvent: methyl ethyl ketone / cyclohexanone = 1/1) These were stirred and mixed by a disper, A body-containing intermediate liquid "was prepared.

Preparation of Particle Dispersion (1) Preparation of Tospearl 105 Particle Dispersion (Large Particle) Tospearl 105 particle dispersion was prepared according to the following formulation. Tospearl 105 (average primary particle size: 0.5 μm) 10 g Diacetyl cellulose solution 190 g (solid content: 3%, solvent: methyl ethyl ketone / cyclohexanone = 1/1) While cooling with ice and stirring, an ultrasonic homogenizer “SONIFIER
450 (manufactured by BRANSON Corp.) "for 1 hour. However, in the case of Sample 2-G of the present invention, when preparing a dispersion of Tospearl 105, the dispersion was performed for 1 hour with a binder-free dispersion medium in which methylethylketone / cyclohexanone = 1/1 without using a diacetylcellulose solution.

(2) Preparation of Seahoster KEP70 Particle Dispersion (Large Particle) A Seahoster KEP70 particle dispersion was prepared according to the following formulation. Sea hoster KEP70 (average primary particle size 0.7 μm) 10 g Diacetyl cellulose solution 190 g (solid content 3%, solvent: methyl ethyl ketone / cyclohexanone = 1/1) While cooling with ice and stirring, ultrasonic homogenizer “SONIFIER
450 (manufactured by BRANSON Corp.) "for 1 hour.

(3) Preparation of AKP20 particle dispersion (large particles) An AKP20 particle dispersion was prepared according to the following formulation. AKP20 (average primary particle size: 0.6 μm) 10 g Diacetyl cellulose solution 190 g (solid content: 3%, solvent: methyl ethyl ketone / cyclohexanone = 1/1) While cooling with ice and stirring, an ultrasonic homogenizer “SONIFIER450 (manufactured by BRANSON Corporation)” For 3 hours. (4) Preparation of HIT100 Particle Dispersion (Fine Particles) A sand mill (1 / 4G sand mill with a ceramic coating on the rotating disk in the vessel) with the following formulation
At 2000 rpm for 12 hours. The media used was zirconia beads of 1 mmφ. HIT100 (α-alumina, average primary particle size 0.10 μm) 37 g Silane coupling agent 8.4 g [3- (poly (degree of polymerization 10) oxyethynyl) oxypropyltrimethoxysilane] diacetyl cellulose solution 324.6 g (solid content 4.5%, solvent: methyl ethyl ketone / cyclohexanone = 1/1)

(5) Colloidal silica particle dispersion (fine particles) "MEK-silica sol" manufactured by Nissan Chemical Industries, Ltd. was used. This is a dispersion of colloidal silica having an average primary particle size of 0.015 μm using methyl ethyl ketone as a dispersion medium, and has a solid content of 30%.

Preparation of Second Layer Coating Solution (Comparative Example 1-A Sample) The above-mentioned magnetic substance-containing intermediate liquid 3500 g Tospearl 105 dispersion 147 g Crosslinking agent [1]: 8 g of millionate MR-400 (manufactured by Nippon Polyurethane Co., Ltd.) HIT100 Dispersion liquid 147 g Methyl ethyl ketone 15.5 g Cyclohexanone 15.5 g The coating amount of this coating liquid was 29.3 cc / m ² with a wire bar.
It was applied so that Drying was performed at 110 ° C. At this time, Tospearl 105 was applied at 50 mg / m ² .

3) Third Layer Preparation of Coating Solution for Third Layer The following compound was added to 482 g of the stock dispersion B-1 to prepare a coating solution. The following compound _{0.73g C 6 H 13 CH (OH} ) C 10 H 20 COOC 40 H 81 C 8 F 17 SO 2 N (C 3 H 7) (CH 2 CH 2 O) 4 - (CH 2) 4 SO 3 Na polyester modified silicone solution 2.88 g (BYK chemi Japan Co., Ltd., trade name: BYK310, solids content 25%) was coated with the slip layer coating solution in a coating amount of 10.4cc / m ^2.

Next, the evaluation of the sample will be described. a) Evaluation of magnetic input / output performance A prepared sample slit to a width of 24 mm and a length of 300 m was magnetically recorded in advance by a 6 kHz FM signal at a conveying speed of 100 mm / sec. After this, Fuji Photo Film's CN-16
Development processing was performed according to the X chemical prescription. The developing machine is a cine-type automatic developing machine FNCP-9 manufactured by Fuji Photo Film Co., Ltd.
00 was used. For the sample after the development processing, the gap 5
Using a general-purpose magnetic reproducing head having a winding of 2,000 μm and a number of turns of 2000, the recorded signal is reproduced using an amplifier having a gain of about 95 dB, and each of the reproduced signals is examined as follows. An evaluation was performed. Samples that remain on the transparent magnetic recording layer side surface and transfer and accumulate on the surface of the magnetic head during running of the sample, due to the loss of the signal amplitude due to space loss loss It was adopted because the number of dropouts increased due to the smaller size. When the magnitude of each reproduced signal (reproduced output) becomes 35% or less of the ideal magnitude of the reproduced signal when the magnetic head is free from dirt, it is defined as "dropout". 10 times or more × (NG) Dropout is 5 times or more and less than 10 times △ (NG) Dropout is 3 times or more and less than 5 times 〇 Dropout is 1 time or more and 3 times It was judged as less than 時 when there was no dropout 〇〇〇.

B) Measurement of Optical Contact Area The optical contact area was measured using a microtopograph manufactured by Toyo Seiki Seisaku-sho, Ltd. The measurement was performed at 25 ° C., 60%, a load of 16 kgf / cm ² , and a measurement wavelength of 0.5 μm. In this measurement, optically
It is measured as 100% when the sample surface is smooth, and the value decreases as the sample surface becomes less smooth.

C) Evaluation of scratch resistance After the photosensitive material after the development processing was conditioned at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, a diamond needle having a tip of 0.25 mmR was vertically applied to the backing layer to apply a continuous load. And scratched at a speed of 60 cm / min. The light-sensitive material after the scratching was enlarged and printed 16 times, and the load (g) when scratches began to appear on the screen was defined as the scratching strength. The larger the value, the better the scratch resistance. e) Amount of transfer to roller The sample surface was brought into contact with a metal roller, pressure was applied to 5 kg / cm ² , the mixture was left at 110 ° C for 2 hours, and the amount of wax transferred to the roller was quantified.

(Comparative sample 1-a) Except that the dispersion used for the third layer coating solution was changed to B2, it was prepared in exactly the same manner as in 1-A. This is designated as Comparative Example Sample 1-A. (Comparative Example Sample 1-C) Except that the dispersion used for the third layer coating liquid was changed to B4, it was prepared in exactly the same manner as in 1-A. This is designated as Comparative Example Sample 1-C. (Comparative sample 1-D) Except that the dispersion used for the third layer coating liquid was changed to C4, the same procedure as in 1-A was used. This is designated as Comparative Example Sample 1-D. (Inventive sample 1-A) Except that the dispersion used for the third layer coating solution was changed to C4, it was prepared in exactly the same manner as in 1-A. This is designated as Sample 1-A of the present invention. (Sample 1-B of the Present Invention) Except that D3 was used as the dispersion liquid for the third layer coating liquid, the same preparation as in 1-A was made. This is designated as Sample 1-B of the present invention.

(Comparative Sample 1-E) Except that the formulation of the second layer coating solution was changed as follows, and the dispersion of the third layer coating solution was changed to C-4, it was completely the same as Sample 1-A of the present invention. Produced. This is designated as Comparative Example Sample 1-O. Intermediate liquid containing magnetic material 3500 g Colloidal silica dispersion (solid content 30%) 98 g Crosslinking agent [1]: Millionate MR-400 (manufactured by Nippon Polyurethane Co., Ltd.) 8 g Diacetyl cellulose solution 147 g (solid content 4.5%, solvent: methyl ethyl ketone) / Cyclohexanone = 1/1) methyl ethyl ketone 40g cyclohexanone 40g

(Invention Sample 2-A) The formulation of the coating solution for the second layer was changed to the following, and an additional layer of the following formulation serving as an intermediate layer was further added between the second and third layers. The sample was prepared in exactly the same manner as Sample 1-A of the present invention, except that the dispersion of the third layer was C4. This is designated as Sample 2-A of the present invention. <Preparation of coating solution for second layer> Intermediate liquid containing magnetic material 3500 g Diacetyl cellulose solution 294 g (solid content 4.5%, solvent: methyl ethyl ketone / cyclohexanone = 1/1) Crosslinking agent [1]: Millionate MR-400 (Nippon Polyurethane Co., Ltd.) 8 g) methyl ethyl ketone 15.5 g cyclohexanone 15.5 g <Preparation of coating solution for intermediate layer> 36 g of diacetyl cellulose solution (solid content: 4.5%, solvent: methyl ethyl ketone / cyclohexanone = 1/1) methyl ethyl ketone 909 g cyclohexanone 909 g Tospearl 105 dispersion 87 g AKP20 dispersion Liquid 9g Colloidal silica dispersion (solid content 30%) 51g This coating liquid was coated with a wire bar at an application amount of 10.4 cc / m ^2.
It was applied so that Drying was performed at 110 ° C.

[0059]

[Table 2]

As can be seen from Table 2, in the sample of the present invention,
The effect of improving the magnetic input / output performance, scratch resistance and roller transfer is remarkable, and an excellent transparent magnetic recording medium having both reliable magnetic input / output performance and transparency can be provided.

(Others-Sample of the Present Invention-Part 2) In all of the samples of the present invention described above, the coating amount of the magnetic material in the second layer was 0.6 times, and the emulsion layer was a reverse color emulsion layer. In the same manner as in Sample 101 of Example 1, except that the developing process was carried out by a developing method for a color reversal photosensitive material as shown in JP-A-2-854 Example 1, When the same procedures were performed, the same improvement effect (result) was obtained, and an excellent transparent magnetic recording medium with a silver halide emulsion layer having good magnetic input / output performance and good production suitability was obtained.

[0062]

According to the present invention, it is possible to provide an excellent transparent magnetic recording medium having both reliable magnetic input / output performance and manufacturing suitability.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10M 171/06 C10M 171/06 G03C 1/00 GAP G03C 1/00 GAPE 1/76 502 1/76 502 G11B 5/633 G11B 5 / 633 // C10N 20:00 20:06 40:18

Claims (6)

[Claims] 1. A magnetic recording medium having a magnetic recording layer containing at least one magnetic particle on a support, wherein at least one of the layers in the same or different layer on the side of the magnetic recording layer has an average primary particle size. It contains two or more kinds of inorganic or organic particles having different diameters, and has a melting point of at least one in the same layer or / and different layer on the magnetic recording layer side.
A transparent magnetic recording medium characterized by being coated with a wax dispersion at 0 ° C. or higher. 2. The transparent magnetic recording medium according to claim 1, wherein the wax mainly comprises at least one compound represented by the general formula (I) or (II). General formula _{(I) R 1 -X 1 -R} 2 Formula _{(II) R 3 -X 2 -R} 4 - (X 3 -R 5) in _n Formula (III) R ₆ OBH formula, R ₁ to R ₃ , R ₅ and R ₆ are a substituted or unsubstituted saturated or unsaturated hydrocarbon group having 10 to 70 carbon atoms, including straight, branched and cyclic, and R ₄ is a divalent or more substituted C 10 to C 50 hydrocarbon group. Alternatively, it is an unsubstituted saturated, unsaturated or linear, branched or cyclic hydrocarbon group. X ₁ ~X ₃ is -COO
-, -OCO-, -CONR-, -NRCO-,
n is an integer of 1 or more. B is a polyalkylene oxide chain. 3. The dispersion is prepared by using a high-pressure homogenizer in a closed tube from a homogenizing chamber to a processing liquid discharge port, and using a device having a back pressure applying device behind the homogenizing chamber. The transparent magnetic recording medium according to claim 1, wherein: 4. The halogen according to claim 1, wherein the transparent magnetic recording medium has at least one silver halide emulsion layer on the opposite side of the magnetic recording layer with the support interposed therebetween. A transparent magnetic recording medium with a silver halide emulsion layer. 5. The transparent magnetic recording medium according to claim 1, wherein the applied amount of the dispersion is 16 mg / m ² or more. 6. The transparent magnetic recording medium according to claim 1, wherein the optical contact area at a wavelength of 0.5 μm under a relative humidity of 60% at 25 ° C. and a load of 16 kg / m ² is 20% or more and 80% or less. 6. The transparent magnetic recording medium according to any one of 1 to 5.